Pharmaceutical therapeutics for articular regeneration and restoration: state-of-the-art technology for screening small molecular drugs

In situ Chemical Reprogramming of Astrocytes into Neurons: A New Hope for the Treatment of Central Neurodegenerative Diseases?

Central neurodegenerative disorders (e.g. Alzheimer's disease (AD) and Parkinson's disease (PD)) are tightly associated with extensive neuron loss. Current therapeutic interventions merely mitigate the symptoms of these diseases, falling short of addressing the fundamental issue of neuron loss. Cell reprogramming, involving the transition of a cell from one gene expression profile to another, has made significant strides in the conversion between diverse somatic cell types. This advancement has been facilitated by gene editing techniques or the synergistic application of small molecules, enabling the conversion of glial cells into functional neurons. Despite this progress, the potential for in situ reprogramming of astrocytes in treating neurodegenerative disorders faces challenges such as immune rejection and genotoxicity(Hong et al., 2013). A novel avenue emerges through chemical reprogramming of astrocytes utilizing small molecules, circumventing genotoxic effects and unlocking substantial clinical utility. Recent studies have successfully demonstrated the in situ conversion of astrocytes into neurons using small molecules. Nonetheless, these findings have sparked debates, encompassing queries regarding the origin of newborn neurons, pivotal molecular targets, and alterations in metabolic pathways. This review succinctly delineates the background of astrocytes reprogramming, meticulously surveys the principal classes of small molecule combinations employed thus far, and examines the complex signaling pathways they activate. Finally, this article delves into the potential vistas awaiting exploration in the realm of astrocytes chemical reprogramming, heralding a promising future for advancing our understanding and treatment of neurodegenerative diseases.

Molecular biomarker approaches to prevention of post-traumatic osteoarthritis

Up to 50% of individuals develop post-traumatic osteoarthritis (PTOA) within 10 years following knee-joint injuries such as anterior cruciate ligament rupture or acute meniscal tear. Lower-extremity PTOA prevalence is estimated to account for ≥12% of all symptomatic osteoarthritis (OA), or approximately 5.6 million cases in the USA. With knowledge of the inciting event, it might be possible to 'catch PTOA in the act' with sensitive imaging and soluble biomarkers and thereby prevent OA sequelae by early intervention. Existing biomarker data in the joint-injury literature can provide insights into the pathogenesis and early risk trajectory related to PTOA and can help to elucidate a research agenda for preventing or slowing the onset of PTOA. Non-traumatic OA and PTOA have many clinical, radiological and genetic similarities, and efforts to understand early risk trajectories in PTOA might therefore contribute to the identification and classification of early non-traumatic OA, which is the most prevalent form of OA.

Discovery of Taurocholic Acid Sodium Hydrate as a Novel Repurposing Drug for Intervertebral Disc Degeneration by Targeting MAPK3

OBJECTIVE

Nowadays, more than 90% of people over 50 years suffer from intervertebral disc degeneration (IDD), but there are exist no ideal drugs. The aim of this study is to identify a new drug for IDD.

METHODS

An approved small molecular drug library including 2040 small molecular compounds was used here. We found that taurocholic acid sodium hydrate (NAT) could induce chondrogenesis and osteogenesis in mesenchymal stem cells (MSCs). Then, an in vivo mouse model of IDD was established and the coccygeal discs transcriptome analysis and surface plasmon resonance analysis (SPR) integrated with liquid chromatography-tandem mass spectrometry assay (LC-MS) were performed in this study to study the therapy effect and target proteins of NAT for IDD. Micro-CT was used to evaluate the cancellous bone. The expression of osteogenic (OCN, RNX2), chondrogenic (COL2A1, SOX9), and the target related (ERK1/2, p-ERK1/2) proteins were detected. The alkaline phosphatase staining was performed to estimate osteogenic differentiation. Blood routine and blood biochemistry indexes were analyzed for the safety of NAT.

RESULTS

The results showed that NAT could induce chondrogenesis and osteogenesis in MSCs. Further experiments confirmed NAT could ameliorate the secondary osteoporosis and delay the development of IDD in mice. Transcriptome analysis identified 128 common genes and eight Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for NAT. SPR-LC-MS assay detected 57 target proteins for NAT, including MAPK3 (mitogen-activated protein kinase 3), also known as ERK1 (extracellular regulated protein kinase 1). Further verification experiment confirmed that NAT significantly reduced the expression of ERK1/2 phosphorylation.

CONCLUSION

NAT would induce chondrogenesis and osteogenesis of MSCs, ameliorate the secondary osteoporosis and delay the progression of IDD in mice by targeting MAPK3.Furthermore, MAPK3, especially the phosphorylation of MAPK3, would be a potential therapeutic target for IDD treatment.

Engineered biochemical cues of regenerative biomaterials to enhance endogenous stem/progenitor cells (ESPCs)-mediated articular cartilage repair

As a highly specialized shock-absorbing connective tissue, articular cartilage (AC) has very limited self-repair capacity after traumatic injuries, posing a heavy socioeconomic burden. Common clinical therapies for small- to medium-size focal AC defects are well-developed endogenous repair and cell-based strategies, including microfracture, mosaicplasty, autologous chondrocyte implantation (ACI), and matrix-induced ACI (MACI). However, these treatments frequently result in mechanically inferior fibrocartilage, low cost-effectiveness, donor site morbidity, and short-term durability. It prompts an urgent need for innovative approaches to pattern a pro-regenerative microenvironment and yield hyaline-like cartilage with similar biomechanical and biochemical properties as healthy native AC. Acellular regenerative biomaterials can create a favorable local environment for AC repair without causing relevant regulatory and scientific concerns from cell-based treatments. A deeper understanding of the mechanism of endogenous cartilage healing is furthering the (bio)design and application of these scaffolds. Currently, the utilization of regenerative biomaterials to magnify the repairing effect of joint-resident endogenous stem/progenitor cells (ESPCs) presents an evolving improvement for cartilage repair. This review starts by briefly summarizing the current understanding of endogenous AC repair and the vital roles of ESPCs and chemoattractants for cartilage regeneration. Then several intrinsic hurdles for regenerative biomaterials-based AC repair are discussed. The recent advances in novel (bio)design and application regarding regenerative biomaterials with favorable biochemical cues to provide an instructive extracellular microenvironment and to guide the ESPCs (e.g. adhesion, migration, proliferation, differentiation, matrix production, and remodeling) for cartilage repair are summarized. Finally, this review outlines the future directions of engineering the next-generation regenerative biomaterials toward ultimate clinical translation.

Shang-Ke-Huang-Shui and coptisine alleviate osteoarthritis in the knee of monosodium iodoacetate-induced rats through inhibiting CXCR4 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Shang-Ke-Huang-Shui (SKHS) is a classic traditional Chinese medicine formula originally from the southern China city of Foshan. It has been widely used in the treatment of osteoarthritis (OA) but underlying molecular mechanisms remain unclear.

AIM OF STUDY

Recently, activation of C-X-C chemokine receptor type 4 (CXCR4) signaling has been reported to induce cartilage degradation in OA patients; therefore, inhibition of CXCR4 signaling has becoming a promising approach for OA treatment. The aim of this study was to validate the cartilage protective effect of SKHS and test whether the anti-OA effects of SKHS depend on its inhibition on CXCR4 signaling. Additionally, CXCR4 antagonist in SKHS should be identified and its anti-OA activity should also be tested in vitro and in vivo.

METHODS

The anti-OA effects of SKHS and the newly identified CXCR4 antagonist was evaluated by monosodium iodoacetate (MIA)-induced rats. The articular cartilage surface was examined by hematoxylin and eosin (H&E) staining and Safranin O-Fast Green (S-F) staining whereas the subchondral bone was examined by micro-CT. CXCR4 antagonist screenings were conducted by molecular docking and calcium response assay. The CXCR4 antagonist was characterized by UPLC/MS/MS. The bulk RNA-Seq was conducted to identify CXCR4-mediated signaling pathway. The expression of ADAMTS4,5 was tested by qPCR and Western blot.

RESULTS

SKHS protected rats from MIA-induced cartilage degradation and subchondral bone damage. SKHS also inhibited CXCL12-indcued ADAMTS4,5 overexpression in chondrocytes through inhibiting Akt pathway. Coptisine has been identified as the most potent CXCR4 antagonist in SKHS. Coptisine reduced CXCL12-induced ADAMTS4,5 overexpression in chondrocytes. Furthermore, in MIA-induced OA model, the repaired cartilage and subchondral bone were observed in the coptisine-treated rats.

CONCLUSION

We first report here that the traditional Chinese medicine formula SKHS and its predominate phytochemical coptisine significantly alleviated cartilage degradation as well as subchondral bone damage through inhibiting CXCR4-mediated ADAMTS4,5 overexpression. Together, our work has provided an important insight of the molecular mechanism of SKHS and coptisine for their treatment of OA.

Direct Reprograming of Mouse Fibroblasts into Dermal Papilla Cells via Small Molecules

The reprogramming of somatic fibroblasts into alternative cell linages could provide a promising source of cells for regenerative medicine and cell therapy. However, the direct conversion of fibroblasts into other functional cell types is still challenging. In this study, we show that dermal-papilla-cell-like cells (DPC-LCs) can be generated by treating fibroblasts, including L929 mouse fibroblast cell lines and somatic mouse fibroblasts, with small molecules. Based on alkaline phosphatase activity and other molecular markers, different compounds or their combinations are needed for converting the two different fibroblasts into DPC-LCs. Notably, we found that TTNPB alone can efficiently convert primary adult mouse fibroblasts into DPC-LCs. DPC-LCs generated from mouse fibroblasts showed a stronger hair-inducing capacity. Transcriptome analysis reveals that expression of genes associated with a hair-inducing capacity are increased in DPC-LCs. This pharmacological approach to generating functional dermal papilla cells may have many important implications for hair follicle regeneration and hair loss therapy.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.